Composite materials are increasingly important as construction components in the building and storage industries. They offer flexibility in design while avoiding durability and weight issues characteristic of conventional materials such as wood and wood products. By combining the advantages of a variety of materials in their core and facing layers, composite materials can be designed and fabricated to optimize price and performance.
Fabrication of composite systems, however, requires bonding various layers together. This is particularly a concern when bonding adjacent dissimilar materials. For example, in multilayer films tie layers produced from adhesive composition layers are typically positioned between the dissimilar layers to be bonded, and the layers then adhered by conventional means. Other applications require good adhesion between a metal and an adjacent layer. For example, nail guns often use nail-collation tape to load nails into the gun, where the nails are adhered to the tape using an adhesive layer. Still other applications include wire and cable, where an aluminum wire must be adhered to the outer layer of low density polyethylene. In composite multilayer pipe applications, an aluminum interior layer is often sandwiched between interior and exterior layers of polypropylene, polyethylene or cross-linked polyethylene. In these structures, adhesive composition layers are required between the polyolefins and aluminum.
Various adhesive compositions have been proposed. For example, functionalized polyolefins have been combined with a base polymer or high ethylene content materials such as ethylene-propylene copolymers or ethylene-propylene-diene terpolymers, for example as described in U.S. Pat. Nos. 4,087,587, 4,298,712, 4,487,885, 4,774,144, and 5,367,022. Additionally, propylene elastomer-containing material has been disclosed in U.S. Publ. No. 2008/0032148. However, a continuing need exists for compositions providing superior levels of adhesion for today's demanding applications. It has unexpectedly been found that compositions comprising a first copolymer of butene-1 and propylene, a second copolymer of ethylene and a comonomer selected from butene-1, hexene-1 and octene-1; a polyolefin grafted with an ethylenically unsaturated carboxylic acid or acid derivative; and an olefin polymer resin exhibits superior adhesion performance.